The Effect of Some Urinary Constituents on the in Vitro Nucleation and Growth Kinetics of Calcium Oxalate

Abstract

The in vitro crystallization of calcium oxalate has been investigated by many workers in the field of renal stone disease with a view to providing some insight into the cause as well as the possible treatment of the disorder1–4. Using different techniques and under a variety of conditions, nucleation, growth and aggregation characteristics of this compound have been examined. In particular, the inhibitory effect of several compounds has received a lot of attention5–10. These studies however have all been limited to static, supersaturated systems and have failed to produce definitive nucleation and growth kinetics. Today the role of inhibitors is recognized as being an important factor in the genesis of renal calculi and recent studies have accordingly been directed towards quantitizing this inhibitory power. In attaining accurate quantitative crystallization kinetics, two important approaches have been utilized. The first employs the use of a continuous crystallizer system and the second involves particle size distribution analysis using a Coulter counter. Finlayson11 was the first to describe the usefulness of a continuous crystallizer as a simple urinary tract model while Robertson and Peacock4 determined the size distribution of calcium oxalate crystalluria in normal and stone forming patients. Miller, Randolph and Drach combined these ideas and have determined the crystallization kinetics of calcium oxalate in simulated urine12 and have also measured the inhibition of calcium oxalate crystallization by pyrophosphate and methylene blue13.